1. Field of the Invention
The present invention relates to an electric motor, more particularly to a stator for an electric motor.
2. Description of the Related Art
An electric motor includes the two basic elements of a stator and a rotor. By using a three-phase drive method, a rotating magnetic field is produced in the stator. A magnetic field of the rotor is established such that the rotor follows the rotating magnetic field of the stator.
FIG. 1 shows a conventional stator for a three-phase AC (alternating current) motor. The stator includes three windings 10 of differing large, medium, and small dimensions, and each formed into a closed sinusoidal shape. An adhesive is used to attach the windings 10 to one another such that the medium winding 10 is sleeved over the small winding 10, and the large winding 10 is sleeved over the medium winding 10. Each of the windings 10 has a winding start end and a winding finish end. The winding start ends of the windings 10 are electrically and respectively coupled to control lines (U, V, W), which are supplied with AC signals that are out of phase with one another. The winding finish ends of the windings 10 are electrically coupled to a common line (COM).
A drawback of the aforesaid conventional stator, however, is that manufacture of the same is difficult. In particular, not only is the formation of the sinusoidal shape of each of the windings 10 difficult, but each of the three windings 10 must be manufactured to precise dimensions to allow for the sleeved configuration described above. In addition, it is necessary that the sinusoidal shapes of the windings 10 be uniformly offset from each other so that the magnetic poles are uniformly distributed. Such offsetting to any high degree of accuracy is difficult to achieve. Finally, since each of the large, medium, and small windings 10 is individually and separately manufactured, complicated equipment is required for production of the stator.